An apparatus based on the conventional technology is disclosed in "workpieces discharging apparatus for a laser machining apparatus" and in Japanese Utility Model Publication No. 28711/1992. A laser machining apparatus based on the conventional technology may be seen with reference to the front view shown in FIG. 10, the top view shown in FIG. 11, and the side view shown in FIG. 12.
In each of the figures above, the reference numeral 1 indicates a machining table on which a workpiece 2 is mounted and supported by a support pin 3. The table 1 moves from side to side in FIG. 10 and FIG. 11. A machining head 4 moves perpendicularly to the moving direction of the machining table 1, above the machining table 1 and the workpiece 2, and irradiates a laser beam onto the workpiece 2. A guiding unit and a driving unit for the machining table 1 and the machining head 4 are not shown in the figures, but it is assumed that the machining table 1 moves in the X direction and the machining head 4 moves in the Y direction, and when assembled with a control unit not shown herein, it is possible to freely machine the workpiece 2 with a laser beam within the X-Y plane.
In this laser machining for cutting, the workpiece 2 is supported by the support pins 3 each having a needle-like tip so that a laser beam from the machining head 4 reaches positions located under the workpiece 2. For this reason, on the machining table 1 a space is provided so that workpieces, machined pieces (called chips hereinafter), and products can drop therethrough to a position under the machining table 1.
A chip conveyor 5 is provided under the machining table 1 in the entire fixed section over which the machining table can move. Thus, chips dropping after the workpiece is subjected to laser machining via the dropping space to below the machining table are received and carried out of the machining table movable area. The reference numeral 6 is a recovery box, in which chips carried by the chip conveyor 5 are collected.
In the conventional type of apparatus as described above, an area within the X-Y plane where laser machining is executed is limited to an area where the machining head 4 moves. Unless chips are substantially large (when chips are large, the chips do not drop because of interference by the support pins 3), when machining under ordinary conditions, chips drop in a zone having a specified width within the area where the machining head 4 moves. However, sometimes chips will hang on the support pins 3 on the machining table 1 or on some other structure on the machining table 1. As a result, the chips may drop onto an area other than that described above, namely in the entire area where the machining table 1 moves, so that the above-described chip conveyor 5 must be provided in the entire area where the machining table 1 moves to collect all chips without fail and irrespective of the machining sequence. It should be noted that the reference numeral 7 indicates an operator, and the normal operation of a laser machining apparatus is carried out at the place shown in this figure.
Technical documents relating to this include Japanese Patent Laid-Open Publication No. 262939/1990 disclosing the "parts take-out device", Japanese Utility Model Laid-Open Publication No. 2594/1988 disclosing the "chips discharging device for a laser machining apparatus", Japanese Patent Laid-Open Publication No. 8065/1993 disclosing the "automatic high speed cutting device for lengthy rod-like material", Japanese Utility Model Laid-Open Publication No. 16291-1990 disclosing the "product take-out device for a laser machining apparatus", and Japanese Patent Laid-Open Publication No. 159267/1982 disclosing the "metallic material melting/cutting device".
Laser machining apparatus based on the conventional technology, having the configuration as described above, has the following problems:
1) Firstly, it is necessary to provide a lengthy chip conveyor in the machining apparatus, which results in a high cost for the apparatus. PA1 2) Secondly, because of the lengthy and large size of the chip conveyor, work such as removing or reassembling the chip conveyor can not be carried out easily, maintenance of the chip conveyor is very difficult, and workability is very poor. PA1 3) Thirdly, the operator must go to the front side of the machining apparatus to remove chips, which results in low operability of the apparatus.
Also, the size of this type of laser machining apparatus may be from 4 m (length).times.5 m (width) up to max. 5 m (length).times.9 m (width) also. For this reason, also a chip conveyor for this kind of large system can be very large.